Hello Bobby! Thanks for this patchset! Small comment below:
On 10.06.2023 03:58, Bobby Eshleman wrote:
> This commit drops the transport->dgram_dequeue callback and makes
> vsock_dgram_recvmsg() generic. It also adds additional transport
> callbacks for use by the generic vsock_dgram_recvmsg(), such as for
> parsing skbs for CID/port which vary in format per transport.
>
> Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
> ---
> drivers/vhost/vsock.c | 4 +-
> include/linux/virtio_vsock.h | 3 ++
> include/net/af_vsock.h | 13 ++++++-
> net/vmw_vsock/af_vsock.c | 51 ++++++++++++++++++++++++-
> net/vmw_vsock/hyperv_transport.c | 17 +++++++--
> net/vmw_vsock/virtio_transport.c | 4 +-
> net/vmw_vsock/virtio_transport_common.c | 18 +++++++++
> net/vmw_vsock/vmci_transport.c | 68 +++++++++++++--------------------
> net/vmw_vsock/vsock_loopback.c | 4 +-
> 9 files changed, 132 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index 6578db78f0ae..c8201c070b4b 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -410,9 +410,11 @@ static struct virtio_transport vhost_transport = {
> .cancel_pkt = vhost_transport_cancel_pkt,
>
> .dgram_enqueue = virtio_transport_dgram_enqueue,
> - .dgram_dequeue = virtio_transport_dgram_dequeue,
> .dgram_bind = virtio_transport_dgram_bind,
> .dgram_allow = virtio_transport_dgram_allow,
> + .dgram_get_cid = virtio_transport_dgram_get_cid,
> + .dgram_get_port = virtio_transport_dgram_get_port,
> + .dgram_get_length = virtio_transport_dgram_get_length,
>
> .stream_enqueue = virtio_transport_stream_enqueue,
> .stream_dequeue = virtio_transport_stream_dequeue,
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> index c58453699ee9..23521a318cf0 100644
> --- a/include/linux/virtio_vsock.h
> +++ b/include/linux/virtio_vsock.h
> @@ -219,6 +219,9 @@ bool virtio_transport_stream_allow(u32 cid, u32 port);
> int virtio_transport_dgram_bind(struct vsock_sock *vsk,
> struct sockaddr_vm *addr);
> bool virtio_transport_dgram_allow(u32 cid, u32 port);
> +int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid);
> +int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port);
> +int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len);
>
> int virtio_transport_connect(struct vsock_sock *vsk);
>
> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
> index 0e7504a42925..7bedb9ee7e3e 100644
> --- a/include/net/af_vsock.h
> +++ b/include/net/af_vsock.h
> @@ -120,11 +120,20 @@ struct vsock_transport {
>
> /* DGRAM. */
> int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
> - int (*dgram_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
> - size_t len, int flags);
> int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
> struct msghdr *, size_t len);
> bool (*dgram_allow)(u32 cid, u32 port);
> + int (*dgram_get_cid)(struct sk_buff *skb, unsigned int *cid);
> + int (*dgram_get_port)(struct sk_buff *skb, unsigned int *port);
> + int (*dgram_get_length)(struct sk_buff *skb, size_t *length);
> +
> + /* The number of bytes into the buffer at which the payload starts, as
> + * first seen by the receiving socket layer. For example, if the
> + * transport presets the skb pointers using skb_pull(sizeof(header))
> + * than this would be zero, otherwise it would be the size of the
> + * header.
> + */
> + const size_t dgram_payload_offset;
>
> /* STREAM. */
> /* TODO: stream_bind() */
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index efb8a0937a13..ffb4dd8b6ea7 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -1271,11 +1271,15 @@ static int vsock_dgram_connect(struct socket *sock,
> int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
> size_t len, int flags)
> {
> + const struct vsock_transport *transport;
> #ifdef CONFIG_BPF_SYSCALL
> const struct proto *prot;
> #endif
> struct vsock_sock *vsk;
> + struct sk_buff *skb;
> + size_t payload_len;
> struct sock *sk;
> + int err;
>
> sk = sock->sk;
> vsk = vsock_sk(sk);
> @@ -1286,7 +1290,52 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
> return prot->recvmsg(sk, msg, len, flags, NULL);
> #endif
>
> - return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
> + if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> + return -EOPNOTSUPP;
> +
> + transport = vsk->transport;
> +
> + /* Retrieve the head sk_buff from the socket's receive queue. */
> + err = 0;
> + skb = skb_recv_datagram(sk_vsock(vsk), flags, &err);
> + if (!skb)
> + return err;
> +
> + err = transport->dgram_get_length(skb, &payload_len);
> + if (err)
> + goto out;
> +
> + if (payload_len > len) {
> + payload_len = len;
> + msg->msg_flags |= MSG_TRUNC;
> + }
> +
> + /* Place the datagram payload in the user's iovec. */
> + err = skb_copy_datagram_msg(skb, transport->dgram_payload_offset, msg, payload_len);
> + if (err)
> + goto out;
> +
> + if (msg->msg_name) {
> + /* Provide the address of the sender. */
> + DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
> + unsigned int cid, port;
> +
> + err = transport->dgram_get_cid(skb, &cid);
> + if (err)
> + goto out;
> +
> + err = transport->dgram_get_port(skb, &port);
> + if (err)
> + goto out;
Maybe we can merge 'dgram_get_cid' and 'dgram_get_port' to a single callback? Because I see that this is
the only place where both are used (correct me if i'm wrong) and logically both operates with addresses:
CID and port. E.g. something like that: dgram_get_cid_n_port().
Moreover, I'm not sure, but is it good "tradeoff" here: remove transport specific callback for dgram receive
where we already have 'msghdr' with both data buffer and buffer for 'sockaddr_vm' and instead of it add new
several fields (callbacks) to transports like dgram_get_cid(), dgram_get_port()? I agree, that in each transport
specific callback we will have same copying logic by calling 'skb_copy_datagram_msg()' and filling address
by using 'vsock_addr_init()', but in this case we don't need to update transports too much. For example HyperV
still unchanged as it does not support SOCK_DGRAM. For VMCI You just need to add 'vsock_addr_init()' logic
to it's dgram dequeue callback.
What do You think?
Thanks, Arseniy
> +
> + vsock_addr_init(vm_addr, cid, port);
> + msg->msg_namelen = sizeof(*vm_addr);
> + }
> + err = payload_len;
> +
> +out:
> + skb_free_datagram(&vsk->sk, skb);
> + return err;
> }
> EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
>
> diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
> index 7cb1a9d2cdb4..ff6e87e25fa0 100644
> --- a/net/vmw_vsock/hyperv_transport.c
> +++ b/net/vmw_vsock/hyperv_transport.c
> @@ -556,8 +556,17 @@ static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr)
> return -EOPNOTSUPP;
> }
>
> -static int hvs_dgram_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
> - size_t len, int flags)
> +static int hvs_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static int hvs_dgram_get_port(struct sk_buff *skb, unsigned int *port)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static int hvs_dgram_get_length(struct sk_buff *skb, size_t *len)
> {
> return -EOPNOTSUPP;
> }
> @@ -833,7 +842,9 @@ static struct vsock_transport hvs_transport = {
> .shutdown = hvs_shutdown,
>
> .dgram_bind = hvs_dgram_bind,
> - .dgram_dequeue = hvs_dgram_dequeue,
> + .dgram_get_cid = hvs_dgram_get_cid,
> + .dgram_get_port = hvs_dgram_get_port,
> + .dgram_get_length = hvs_dgram_get_length,
> .dgram_enqueue = hvs_dgram_enqueue,
> .dgram_allow = hvs_dgram_allow,
>
> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index e95df847176b..5763cdf13804 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -429,9 +429,11 @@ static struct virtio_transport virtio_transport = {
> .cancel_pkt = virtio_transport_cancel_pkt,
>
> .dgram_bind = virtio_transport_dgram_bind,
> - .dgram_dequeue = virtio_transport_dgram_dequeue,
> .dgram_enqueue = virtio_transport_dgram_enqueue,
> .dgram_allow = virtio_transport_dgram_allow,
> + .dgram_get_cid = virtio_transport_dgram_get_cid,
> + .dgram_get_port = virtio_transport_dgram_get_port,
> + .dgram_get_length = virtio_transport_dgram_get_length,
>
> .stream_dequeue = virtio_transport_stream_dequeue,
> .stream_enqueue = virtio_transport_stream_enqueue,
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index b769fc258931..e6903c719964 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -797,6 +797,24 @@ int virtio_transport_dgram_bind(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
>
> +int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
> +{
> + return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_cid);
> +
> +int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
> +{
> + return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_port);
> +
> +int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
> +{
> + return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_length);
> +
> bool virtio_transport_dgram_allow(u32 cid, u32 port)
> {
> return false;
> diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> index b370070194fa..bbc63826bf48 100644
> --- a/net/vmw_vsock/vmci_transport.c
> +++ b/net/vmw_vsock/vmci_transport.c
> @@ -1731,57 +1731,40 @@ static int vmci_transport_dgram_enqueue(
> return err - sizeof(*dg);
> }
>
> -static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
> - struct msghdr *msg, size_t len,
> - int flags)
> +static int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
> {
> - int err;
> struct vmci_datagram *dg;
> - size_t payload_len;
> - struct sk_buff *skb;
>
> - if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> - return -EOPNOTSUPP;
> + dg = (struct vmci_datagram *)skb->data;
> + if (!dg)
> + return -EINVAL;
>
> - /* Retrieve the head sk_buff from the socket's receive queue. */
> - err = 0;
> - skb = skb_recv_datagram(&vsk->sk, flags, &err);
> - if (!skb)
> - return err;
> + *cid = dg->src.context;
> + return 0;
> +}
> +
> +static int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
> +{
> + struct vmci_datagram *dg;
>
> dg = (struct vmci_datagram *)skb->data;
> if (!dg)
> - /* err is 0, meaning we read zero bytes. */
> - goto out;
> -
> - payload_len = dg->payload_size;
> - /* Ensure the sk_buff matches the payload size claimed in the packet. */
> - if (payload_len != skb->len - sizeof(*dg)) {
> - err = -EINVAL;
> - goto out;
> - }
> + return -EINVAL;
>
> - if (payload_len > len) {
> - payload_len = len;
> - msg->msg_flags |= MSG_TRUNC;
> - }
> + *port = dg->src.resource;
> + return 0;
> +}
>
> - /* Place the datagram payload in the user's iovec. */
> - err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
> - if (err)
> - goto out;
> +static int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
> +{
> + struct vmci_datagram *dg;
>
> - if (msg->msg_name) {
> - /* Provide the address of the sender. */
> - DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
> - vsock_addr_init(vm_addr, dg->src.context, dg->src.resource);
> - msg->msg_namelen = sizeof(*vm_addr);
> - }
> - err = payload_len;
> + dg = (struct vmci_datagram *)skb->data;
> + if (!dg)
> + return -EINVAL;
>
> -out:
> - skb_free_datagram(&vsk->sk, skb);
> - return err;
> + *len = dg->payload_size;
> + return 0;
> }
>
> static bool vmci_transport_dgram_allow(u32 cid, u32 port)
> @@ -2040,9 +2023,12 @@ static struct vsock_transport vmci_transport = {
> .release = vmci_transport_release,
> .connect = vmci_transport_connect,
> .dgram_bind = vmci_transport_dgram_bind,
> - .dgram_dequeue = vmci_transport_dgram_dequeue,
> .dgram_enqueue = vmci_transport_dgram_enqueue,
> .dgram_allow = vmci_transport_dgram_allow,
> + .dgram_get_cid = vmci_transport_dgram_get_cid,
> + .dgram_get_port = vmci_transport_dgram_get_port,
> + .dgram_get_length = vmci_transport_dgram_get_length,
> + .dgram_payload_offset = sizeof(struct vmci_datagram),
> .stream_dequeue = vmci_transport_stream_dequeue,
> .stream_enqueue = vmci_transport_stream_enqueue,
> .stream_has_data = vmci_transport_stream_has_data,
> diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
> index 5c6360df1f31..2f3cabc79ee5 100644
> --- a/net/vmw_vsock/vsock_loopback.c
> +++ b/net/vmw_vsock/vsock_loopback.c
> @@ -62,9 +62,11 @@ static struct virtio_transport loopback_transport = {
> .cancel_pkt = vsock_loopback_cancel_pkt,
>
> .dgram_bind = virtio_transport_dgram_bind,
> - .dgram_dequeue = virtio_transport_dgram_dequeue,
> .dgram_enqueue = virtio_transport_dgram_enqueue,
> .dgram_allow = virtio_transport_dgram_allow,
> + .dgram_get_cid = virtio_transport_dgram_get_cid,
> + .dgram_get_port = virtio_transport_dgram_get_port,
> + .dgram_get_length = virtio_transport_dgram_get_length,
>
> .stream_dequeue = virtio_transport_stream_dequeue,
> .stream_enqueue = virtio_transport_stream_enqueue,
>
